The invention relates to a plug-in connector with a bushing and with an insulating member arranged in the bushing in the use position, and with elongate, pin-like contactsxe2x80x94contact pins or female contactsxe2x80x94which in the use position are fixed in holes or bores which receive them in the insulating body via projections which engage in groove-like recesses located on the contacts transverse to their length direction. The holes or bores are located with the elongate contacts on an imaginary cylinder concentric to the middle of the bushing or of the insulating member and thus at the same distance from the inner side of the bushing or of the surface of the insulating member. A further contact in the interior of the imaginary cylinder is arranged within a hole or bore and parallel to the other contacts.
Such electrical plug-in connectors are known and have proved to be useful, since the contacts are fixed and retained in the axial direction when the plug-in connector is plugged together with, or released from, a counterpart, which is frequently associated with overcoming clamping forces and consequent exposure of the contacts to a force in their length direction.
The mutual allocation of the projections to the recesses on the plug contacts has heretofore been costly. In many cases the insulating member is formed in a plurality of parts in order to be able to fix the contacts with their recesses to corresponding projections within the insulating member when this is dismantled. This means that it subsequently has to be assembled, so that both production and assembly are to be considered as costly;
Another known solution provides projections, produced integrally with the insulating member, which, when the pin-like contacts are pushed in, at first deflect and then can latch in the recesses on the contacts. This requires a correspondingly elastic material and furthermore expensive molds for the production of such an insulating member.
The invention has as its object to provide an electrical plug-in connector of the kind noted above, which is easy to produce and which, with a one-piece constitution of the insulating member, makes it possible in a simple manner to fix the contacts, whether they are contact pins or female contacts, via recesses and projections engaging therein.
To attain this object, the plug-in contact as noted above further comprises the insulating member having at least one groove, running around its outside and open outward, and intersecting or passing through the holes or bores for the contacts over a portion of their radial extent on their side facing the outside of the insulating member; and in that the groove is arranged on the insulating member at the height at which the recesses of the contacts are located in the use position. A latching or retaining ring is provided, formed of an insulating material and extending at least over a portion of the entire periphery of the insulating member, fitting into the groove of the insulating member and simultaneously engaging in the use position as a projection into the recesses of the contacts. The retaining ring bears at least one inwardly-projecting retaining tongue which in the use position engages into a channel or perforation extending inward from the groove and projects to within the recess of a further contact located in the interior of the imaginary cylinder and its receiving hole or bore.
An integral, one-piece insulating member can be provided in this manner in which corresponding holes or bores are arranged into which the pin-like contacts are to be pushed, the projections fixing these contacts in the axial direction being formed from a common retaining ring, which is located along a groove of the insulating member and intersects or slightly passes through the holes or bores of the contacts, so that the retaining ring located in this groove can engage in the recesses, located at the same height, of the contacts. A multi-part insulating member, or expensive injected projections on the insulating member for axial fixing of the contacts, is thereby avoided.
It is favorable for easy assembly if the retaining ring comprises only a portion of a circle and its two free ends can be moved apart as least so far that their spacing in this deformed state corresponds to the diameter of the insulating member in the region of the floor of the groove. Thus the retaining ring is interrupted and has two free ends, and can be bent such that in spite of its function of enclosing the insulating member in the groove in the use position, it can first be pushed-on from the side. The retaining ring, which can be bent outwardly due to its elasticity, then snaps back into the use position in the groove due to its elasticity and the resulting restoring force and is thereby fixed. At the same time, its elasticity enables it to move slightly aside again when the contacts are pushed into their holes, into which the retaining ring slightly engages.
It is appropriate here if the groove-like recesses on the elongate contacts or contact pins, particularly groove-like recesses running around their circumference, are respectively bounded by a collar or the like, radially outstanding with respect to the contact region, and on the side remote from the recess this collar has a bevel or a cone shape which, on insertion of the contact into its bore, runs on against the retaining ring and deflects this radially until the recess of the contact is in coincidence with the groove of the insulating member, so that the retaining ring then automatically drops into the recess of the contact and thus fixes the contact axially. It follows from this that the contact region proper of the contact has a smaller cross section than this collar and the portion of the contact extending toward the other side.
One of the contacts arranged on an imaginary cylinder can be provided as a grounding contact and left free by the retaining ring, and this grounding contact can be fixed in the axial direction by an electrically conductive retaining spring or the like fitting into the groove of the insulating member and engaging the contact there, particularly gripping and latching the contact with spring arms or the like. This arrangement is advantageous from many aspects, since such plug-in connectors as a rule require a grounding contact. The presence of this grounding contact is used so that the retaining ring has to run only over a portion of the periphery of the insulating member, and thus has to bend outward a correspondingly small amount during assembly, which reduces or avoids the risk of breakage of the retaining ring when mounting it. At the same time an appropriate solution results for the fastening of the grounding contact, in which the presence of the groove running around the insulating member can be correspondingly used. The retaining ring of the grounding contact, namely a retaining spring, can also likewise form the grounding contact connection.
This results in all in an arrangement in which not only easy production, but also a very easy and nevertheless effective assembly are made possible, in that the retaining ring is first placed on the insulating member in its groove, and then the contacts are pushed in the axial direction into the holes or bores such that their own contact regions are situated to the front in the direction of insertion. With their conical region or projection, they then displace the retaining ring, which then however automatically falls into its recess again and thus effects the fastening. Since the retaining ring is resiliently elastic, it can move aside until, during axial insertion, the recess of the contact reaches this region, and the retaining ring can then spring back again. Due to the elasticity of the retaining ring, the contact pins are thus already secured after insertion, and this also holds for a contact pin in an inner position, which engages with a corresponding conical projection or region on the radially inward-facing tongue of the retaining ring and can displace this radially outward, which is likewise possible due to the elasticity of the retaining ring.
In the use position, the free ends of the retaining ring are then arranged on both sides of the grounding contact and spaced apart from this. The inward-projecting retaining tongue, penetrating a corresponding opening or channel of the insulating, member makes sure of the exact and correct positioning of the retaining ring.
In the final use position, the retaining ring is then secured, by the bushing which receives the insulating member, and which as a rule forms the plug housing, against an undesired bending up.
The retaining spring for the grounding contact can be formed of metal or of electrically conductive plastic, and can have on its outside a bead or projection, in particular, which in the use position protrudes over the surface of the insulating member at least by the play of the insulating member with respect to the bushing and/or the play of the retaining spring in the groove of the insulating member. Electrically conductive plastic can here also be a plastic which is coated or vapor-deposited with metal on the outside. The retaining spring, by means of the bead or projection, also projects slightly in the use position over the surface of the insulating member, so that in each case there results an electrical clamping contact for the grounding contact to the bushing, which as a rule is metallic, so that further measures for connecting the grounding contact are not necessary. Thus the groove arranged on the insulating member is found to be advantageous, since besides receiving the retaining ring, it also receives the retaining spring for the grounding contact in a simple manner and can keep it in contact with the outer bushing.
The cross section of the retaining ring almost fills the cross section of the groove in the use position, or at least the radial extent or width of the retaining ring can correspond to that of the groove, and the bushing receiving the insulating member can accordingly fix the use position of the retaining ring. In practice, the outer circumferential side of the retaining ring forms in this manner an extension of the outer surface of the insulating member; that is, the retaining ring can be about flush with the surface of the insulating member in the use position.
The already mentioned retaining tongue of the retaining ring, projecting radially inward, can be of a concave shape at its end and thereby can be at least partially adapted to the circumferential shape at the base of the recess of the contact to be held by it. The end of the retaining tongue can thus receive a concave curvature which corresponds to the radius of the contact within its recess, so that as large as possible a contact surface results between the retaining tongue and this contact, and the contact is partially encompassed by this retaining tongue. The region of the retaining tongue which engages in the recess of the contact and ensures axial fixing is also correspondingly large.
The retaining ring can extend around more than 180xc2x0 of the insulating member within the groove which runs around the latter, preferably about the whole circumference. Since the retaining ring does not have to extend over the whole circumference, the groove also does not necessarily need to run all the way around; however, this is appropriate and simpler for manufacture. The retaining ring which extends around more than 180xc2x0 permits the already mentioned automatic fixing on the insulating member before the outer bushing encloses the arrangement and prevents and locks the retaining ring from coming out of the groove. However, it is also conceivable to assemble the retaining ring from pieces, which are clamped into the groove and are finally fixed by the bushing.
The free ends of the one-piece retaining ring can be mutually beveled so that they form an insertion funnel for facilitating pushing onto or pushing into the groove of the insulating member. This further facilitates assembly.
The bushing enclosing the insulating member can be formed of metal and form the housing of the plug-in connector, and can if necessary have a thread on its outside. This bushing then receives, in a known manner, a corresponding additional function in that on the one hand it fixes in its interior the insulating member and the retaining ring, and thereby also the contacts, and on the other hand cooperates with the grounding contact and, as a mounting part, can be screwed into a housing or a grip portion or the like.
The bushing can have positioning projections or recesses on its inner side and the insulating member can have deformations fitting together therewith, setting the preselected rotation position of the insulating member when it is axially inserted. The contact pins thereby simultaneously receive their exact positioning relative to the bushing.
An undercut in the axial direction can be provided in the interior of the bushing, behind which undercut there fits at least one retaining tongue which protrudes on the insulating member in the radial direction, and is radially yieldable or can be pressed in. If the insulating member is axially introduced into the bushing, such a retaining tongue automatically fixes the axial position and no further measures are necessary for the axial fixation of the insulating member within the bushing, although they would be possible additionally. In any case, the axial position of the insulating member within the bushing is predetermined and established.
The retaining tongues, elastically resilient or deformable in the radial direction, can here be pivotable about a pivot axis parallel to the mid-axis of the insulating member or of the plug-in connector, and can extend in the circumferential direction of the insulating member. Retaining tongues are frequently known which extend in the axial or plug-in direction and are pivotable around corresponding axes which run transversely. By an arrangement of the retaining tongues somewhat in the circumferential direction, they can be given a relatively long length as well as width, and thereby produce a large-surface connection to the interior behind the undercut of the bushing.
The elastically deformable retaining tongue can border on the groove with a side surface, and can bound the groove, and the retaining ring or the retaining spring can block the elastically yieldable retaining tongue against an axial deformation. Since the retaining tongue is yieldable in the radial direction, a certain axial deformation by corresponding forces is not completely to be excluded, which however is prevented in an advantageous manner by the retaining ring or the retaining spring in the groove of the insulating member. The retaining ring thereby receives a further function.
The retaining tongue can have a latching projection on its outer side, the radial extent of which is equal to or smaller than the deformation path of the retaining tongue in the radial direction. This projection, when pushed into the bushing, springs behind the already mentioned undercut and ensures axial fixation.
It should be mentioned that the width of the retaining ring, and thus its radial dimension, is adapted to the radial distance of the outward-facing surface of a contact or contact pin from the outside of the insulating member, and that the width of the retaining ring in the region of thin contact pins or female contacts is greater than in the region of thicker contact pins or female contacts. The retaining ring can thus be differently shaped in its circumference as regards its width, and adapted to the degree to which the respective contact is distant, due to its own dimension, from the outer surface of the insulating member.
In all, a plug-in electrical connector results in which an insulating member made in one piece can receive a large number of the contact pins, and these can be fixed in the axial direction by a common retaining ring, although at least one of the contacts is arranged within an imaginary cylinder. The basic form of the insulating member is simple, since no projections integrally formed on it are required for defining the contacts. The individually used parts can easily be produced and the whole assembly can likewise be performed simply and rapidly, and nevertheless effectively, and makes sure of an exact location of the individual contacts within the plug-in connector housing and relative to each other.